The gizmo lets you harness the heat from a campfire/gas stove/naked flame heat source to add some juice to a phone or other USB-charged device. It has a max power output of 3W and an average output of 2W, which its makers say can yield between 2 to 4 minutes of phone talk-time per minute of charge

The team behind FlameStower are targeting outdoorsy types, first and foremost, but also reckon their device could be a reliable back-up option to keep in store for use in power outages and storm scenarios.

In keeping with camping kit, the FlameStower folds down to a fairly flat profile so you can chuck it in your backpack.

And unlike the other outdoorsy/back-up option of solar-powered chargers, this bit of kit can work at any time of day — provided you have access to FIRE!

How does FlameStower work exactly? It creates and harnesses a temperature differential to generate electricity using its Thermoelectric Generator. The user exposes its metal blade to a flame to heat it up, while the other side is cooled by a small water reservoir that they fill with water. So really you need both fire and water for this to work. Oh and air, to fuel the fire. It’s elemental.

The hotter the fire, the more charge will be outputted. Albeit, the amount of energy generated is never going to match what you get from a wall outlet. FlameStower’s makers liken its output to charging via a laptop USB port. Which is to say slow and steady, giving you time to appreciate the great outdoors scenery.

The East Palo Alto team behind the device are hoping to raise $15,000 on Kickstarter to get the charger to market — and are around half way there, with 28 days left to run on their campaign.

They are offering the FlameStower to early backers for $70 ($10 off its expected retail price) and are aiming to ship in December.